Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

949
FXUS63 KLOT 152331
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
531 PM CST Sun Feb 15 2026

.KEY MESSAGES...

- Possible fog along/south of I-80 tonight and possible fog north
  of I-80 Monday night.

- Scattered showers and a low chance (20%) of thunderstorms
  early Wednesday morning.

- Elevated fire danger Wednesday with westerly winds gusting to
  30-35 mph.

- Additional rain chances Thursday night/Friday morning and
  possible rain/snow chances Friday night/Saturday.

- Above average temperatures through Thursday.

&&

.DISCUSSION...
Issued at 200 PM CST Sun Feb 15 2026

Highs this afternoon are topping out in the upper 50s for most
locations with a few spots tagging 60. A weak lake breeze has
formed and will turn winds onshore and bring colder temps to
the immediate Lake Michigan shoreline through sunset.

Fog will be a concern again overnight into Monday morning. Much
of the high res guidance is showing fog developing overnight for
areas south of I-80 though there is still quite a bit of
uncertainty for how widespread or how dense this fog may become.
Low level winds also steadily increase in the predawn hours into
Monday morning, which would limit the overall fog potential.
From this distance, included patchy fog mention overnight
through mid morning Monday for areas along/south of I-80 and
trends will need to be monitored this evening.

The increasing low level winds noted above will begin to mix to
the surface by late Monday morning and gusts into the 25-30 mph
are expected Monday. While some cloud cover is expected in the
morning, should at least see partly cloudy skies by afternoon
and probably mostly sunny skies as temps warm into the lower 60s
for most areas and the stronger southwest winds will prevent a
lake breeze Monday afternoon.

A weak frontal boundary is expected to sag south across northern
IL Monday night into Tuesday morning and this may allow for fog
to develop overnight and continue into Tuesday morning, north of
I-80. While confidence is low, frontal boundaries are often the
main element needed for fog development and added patchy fog
for this time period. The proximity of this boundary will
likely maintain southeast winds across much of the area Tuesday,
keeping an onshore wind and colder temps along the IL shore of
Lake Michigan. Though highs in the 50s are expected further
inland.

Low pressure will move northwest across the northern Plains and
northern Great Lakes Tuesday night into Wednesday bringing a
chance for showers to the local area, mainly Tuesday night.
Still some uncertainty for coverage with the blended pops now in
the likely range. Thunder potential looks rather low but
maintained slight chance (20%) mention for late Tuesday night.
Current trends would suggest whatever precipitation develops
will be quickly shifting east around or just after sunrise
Wednesday morning.

Wednesday is then looking dry and windy with high temps warming
into the mid/upper 60s and west/southwest winds gusting 30-35
mph. With relative humidity levels dropping into the 25 to 35
percent range in the afternoon, and depending on the extent of
rain earlier in the morning, an elevated fire danger may
develop, especially across the western half of the cwa.

Models are developing another storm system Thursday that moves
across the local area Thursday night into Friday morning. There
remains quite a bit of uncertainty with this system and its
strength and location. But as trends look now, this may have a
better chance to produce at least isolated thunderstorms for the
local area as well as a higher chance/coverage for showers.
Blended pops are now into the 40-60 percent range and that seems
reasonable from this distance.

Beyond this time period, the overall trend looks colder with
perhaps below normal temps by early next week. The transition to
this possible colder pattern will likely have a storm system
and precipitation nearby, possibly with some snow. cms

&&

.AVIATION /00Z TAFS THROUGH 06Z TUESDAY/...
Issued at 531 PM CST Sun Feb 15 2026

Key Messages for 00Z TAFs:

- Weak lake breeze will affect MDW/GYY/ORD early this evening.

- Potential for a brief period of IFR stratus toward/around
  daybreak Monday morning.

ORD TDWR imagery depicts a weak lake breeze moving slowly
westward toward ORD/MDW approaching 00Z. Not much push behind
it, though will likely see a brief shift to northeast winds and
then becoming light/variable before turning light southwest
later this evening.

Model forecast soundings depict a shallow but strong inversion
developing overnight, with several runs indicating saturation
within that shallow layer occurring predawn. While fog
potential looks to be present to some extent mainly south of the
terminals, stronger southwest flow just above the inversion
supports more of a low stratus potential for the Chicago
terminals toward and around daybreak. Can`t completely rule out
a similar scenario for RFD, though saturation in forecast
soundings appears less impressive there at this time. Have thus
included a tempo mention for a period of IFR cigs roughly in the
10-14Z time frame Monday morning, along with some MVFR/VFR BR,
though would expect this to mix out fairly quickly by mid-
morning. Outside of this early morning stratus potential, VFR
conditions are expected throughout the TAF period.

As we mix after sunrise, a 25-30 kt low-level jet will support
breezy southwest wind conditions with gusts around 25 kts
(potential a few in the 25-30 kt range) from mid-late morning
through the afternoon hours. Winds should diminish and lose the
gustiness with sunset Monday evening. A cold front is expected
to sag into the area Monday night, which would likely provide a
wind shift from southwest to northeast. Timing of the front is
of low confidence at this point, with some guidance bringing it
into the terminals early as 03-06Z Monday evening and others
beyond the end of the current 30-hour TAFs. Given the low
confidence in the front arriving within the forecast period,
have excluded it from the forecasts for now.

Ratzer

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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